It is best known for its role as a consumer champion, but Which? this week moved into the home loans business with the launch of a free service offering personal, tailored mortgage advice over the phone.

Which? Mortgage Advisers went live on Wednesday and is aimed at the consumer organisation's 750,000 members and their family and friends – though if it proves a success, it could be made available to everyone. It promises to "look at every mortgage" on the market, including those only available by going direct to the lender, so people can be sure they are getting the one that is right for them.

The move means Which? is parking its tanks on the lawns of Britain's mortgage brokers, some of whom will have been annoyed by the implied criticism in its promise of "advice from someone people can trust, and who gives them the full picture".

Critics say that as Which? is a consumer champion, there are significant "reputational risks" associated with starting up a commercial venture recommending financial products where your home could be repossessed if you get behind with your payments.

Which? Mortgage Advisers is a new business staffed by a qualified team, and is regulated by the Financial Services Authority.

"Our advice will be tailored to each customer and take into account their individual circumstances, borrowing needs and their plans for the future," says a spokesman. "We've listened to our member requests, and have launched an impartial service."

If you have a friend or relation who is a Which? member, you will be able to use the telephone-based service, though you will need their membership details. Some non-members may decide it is worth joining in order to benefit – the typical Which? "bundle" (subscription to a magazine plus online access) costs £9.75 a month.

However, it will be interesting to see precisely how the organisation defines "family and friends". Will it take a dim view if you email your membership details to everyone you know, so they can use the service, too?

There is no fee for its advice. This isn't unprecedented; there are other "no-fee brokers" out there, most notably London & Country. However, the Which? service is unusual in that its advisers do not receive commission – they are paid a salary.

Some lenders will pay the service a commission for recommending one of their mortgages. However, this will fund the service, with any profits going towards the organisation's campaigning work. "Commission will in no way influence the recommendation that our advisers provide, and on many occasions we will receive no commission at all," says the spokesman.

That is because some banks and building societies reserve their best deals for customers who go direct to them – which usually means no commission payments to brokers who recommend these deals to their clients. For example, HSBC and its First Direct division have never made their mortgages available through brokers.

Which? Mortgage Advisers says that when a customer gets in touch, an adviser will take details, go away and research the market, and send an email with recommendations. The adviser will then call to talk it through.

It says it will not hesitate to recommend a "direct" deal if this is the best mortgage for the customer. However, in that situation, customers will have to fill out the mortgage forms themselves.

If a customer feels more comfortable paying for the advice they receive, this will be possible. They will be charged a fee of 0.5% of the loan, and if the firm receives any commission from the lender, it will refund it to the customer.

Melanie Bien at independent mortgage broker Private Finance says: "It will be interesting to see how the Which? advisers get on, as it's unlikely they will have any former experience. And, with the promise not to pay commission, they won't get the very best people working in this market, anyway. Customers would be better off choosing an established independent mortgage broker with years of experience and a proven track record."

She adds: "The real proof will be when they get something wrong and face a complaint – it will be interesting how that affects the reputation of the wider Which? business."